Abstract
In the present paper the authors studied statistically on the remarkable thunderstorms which occured in Japan during 11 years from 1924 to 1934. They classified the remarkable thunderstorms into two main types, namely the one being of the heat type and the other of the depression type.
The former includes the thunderstorms caused generally by the solar agency. Here we picked up the statistical data of the thunderstorms occured in the four months from May to September, as in this country the thunderstorms of heat type are very frequently experienced in summer season. The thunderstorms which cause the various damages on the electric transmission lines and so on are mainly of this tpye, hence it seems that the statistical investigation of the remarkable thunderstorms of heat type deserves well to the practical purposes (Fig. 1 and 2).
The remarkable thunderstorms of the depression type are, on the other hand, very few in number to investigate them statistically. But, roughly speaking, it is concluded that these are frequently experienced at the western part of the Japan proper and generally they pass over the inland sea from west to east covering more than 500 kms of length (Fig. 3).
